WO2001055043A1

WO2001055043A1 - Low emissivity glass

Info

Publication number: WO2001055043A1
Application number: PCT/JP2001/000442
Authority: WO
Inventors: Masato Hyodo; Koichiro Kiyohara
Original assignee: Nippon Sheet Glass Co., Ltd.
Priority date: 2000-01-25
Filing date: 2001-01-24
Publication date: 2001-08-02

Abstract

A low emissivity glass, characterized in that a silicon oxide film as a first layer is formed on a glass substrate, for example, in a thickness of 100 Å, a tin oxide film as a second layer is formed on the first layer, for example, in a thickness of 250 Å, a silicon oxide film as a third layer is formed on the second layer, for example, in a thickness of 250 Å, and a tin oxide film as a forth layer is formed on the third layer, for example, in a thickness of 3500 Å. The low emissivity glass is free from the formation of NaCl in an electrically conductive film therein and has no tubidness.

Description

Description Low emissivity glass Technical field

The present invention relates to a low-emissivity glass applied to a window glass of a building, an anti-fog window glass of a vehicle, a frozen showcase, a liquid crystal display, a plasma display, and the like. Background art

As a low emissivity glass used as a window glass or the like of a building, a glass having a configuration disclosed in Japanese Patent No. 1788555 is known. As shown in FIG. 3, this low emissivity glass is formed by sequentially forming a tin oxide film as a first layer, a silicon oxide film as a second layer, and a tin oxide film as a third layer on the surface of a glass substrate. The first layer and the second layer reduce the reflection color due to the thin film of the thin film, thereby preventing color unevenness.

On the other hand, methods for forming a thin film on the surface of a glass substrate include a sputtering method, a vacuum evaporation method, a CVD method, and a spray method.In order to efficiently mass-produce high-quality low-emissivity glass, The so-called float method is used to fabricate a glass ribbon serving as a glass substrate, and a raw material gas is sprayed on the surface of the glass ribbon in a high-temperature state in the float bath or after leaving the float bath to utilize the heat energy of the glass ribbon. On-line CVD for forming a film by thermal decomposition or the like on the glass ribbon is known.

If the above-mentioned on-line CVD can form a tin oxide film as the first layer, a silicon oxide film as the second layer, and a tin oxide film as the third layer on the surface of the glass substrate, the cost can be significantly reduced. Although it can be realized, there are the following problems. That is, glass produced by the float bath method is based on soda lime glass and contains an alkali such as Na. The Sn source gas contains halogen such as C 1, and the C 1 reacts with Na to generate a salt (NaCl). The salt produced is usually the size of the visible submicron mouth, and when this salt is incorporated into the membrane, the haze rate (= diffuse transmittance (total transmittance straight transmittance) Z total transmittance) Turbidity occurs, and in particular, the turbidity is partially generated, so that the appearance quality is degraded and defective, and the commercial value is greatly reduced.

On the other hand, if a Sn raw material that does not contain halogen such as C1 is used, for example, tetramethyltin / tetrabutyltin, no salt is formed, but the deposition rate is low and the cost is high. Management is cumbersome and there are environmental issues.

At present, attempts have been made to lower the temperature at which the tin oxide film as the first layer is formed on the glass surface by online CVD to a certain value.However, in this method, the temperature is controlled. In order to improve productivity, it is necessary to add a cooler and other equipment, and the equipment must be changed drastically.In addition, changing the glass conveyance speed on the float bath changes the surface temperature, thereby improving productivity. Can not. Disclosure of the invention

In order to solve the above-mentioned problems, a low-emissivity glass according to the present invention comprises a glass substrate containing an alkali, a silicon oxide film as a first layer, a tin oxide film as a second layer, and a silicon oxide film as a third layer. As the film, a tin oxide film was sequentially formed as a fourth layer. Here, the silicon oxide and tin oxide constituting each layer have a force that occupies most of S i〇 ₂ and S n〇 _{2 in} which the ratio of S i (S n) to O is 1: 2, respectively. There are parts that do not logically make exactly 1: 2, and the present invention includes those parts. By forming a silicon oxide film on the first layer, even if it is a thin film, Na Diffusion) can be prevented. As such an alkali barrier layer, titanium oxide and zirconium oxide can be considered in addition to silicon oxide. Since silicon oxide has almost the same refractive index as glass and does not hinder the effect of reducing the reflection color by the upper layer film (tin oxide + silicon oxide), silicon is the best material.

Further, it is preferable that the fourth layer tin oxide film contains F (fluorine). Inclusion of F (fluorine) increases conductivity, thereby lowering the emissivity of glass and improving heat insulation performance.

The thickness of the silicon oxide film as the first layer is 1 OA or more, the thickness of the tin oxide film as the second layer is 200 to 500 A, and the thickness of the silicon oxide film as the third layer is The thickness is 200 to 500 persons, and the thickness of the tin oxide film as the fourth layer is preferably 250 OA or more, particularly preferably in the range of 3200 A to 3800 A, and if it is about 350 A, The film color can be changed to a cool color.

The reason why the thickness of the silicon oxide film as the first layer is set to 1 OA or more is that the function as an AL force barrier is not sufficiently exhibited if the thickness is less than 1 OA, and the film of the tin oxide film as the second layer is formed. The thickness is set to 200 to 50 OA and the thickness of the silicon oxide film as the third layer is set to 200 to 500 A in order to reduce the interference reflection color of the thin film, and tin oxide as the fourth layer (+ F) The thickness of the film is more than 250 A, preferably between 3200 and 380 A. The vertical thickness specified in JISR 3209 “Insulated double glass” This is to satisfy the emissivity (ε) <0.15 ”. BRIEF DESCRIPTION OF THE FIGURES

【Figure 1】

Online CV as an example of a method for producing a low emissivity glass according to the present invention Diagram explaining D

【Figure 2】

Enlarged cross-sectional view of the low-emissivity glass according to the present invention

[Figure 3]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred Embodiment of the Invention

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a diagram illustrating on-line CVD as an example of a method for producing a low-emissivity glass according to the present invention. The main part is composed of a lift roll 3, which lifts the glass in a strip form from the float bath 2, a slow cooling unit 4 arranged downstream of the float bath 2, and a spray device 5, 6, 7, 8 arranged on the float bath 2. Have been.

The molten glass is continuously poured from the melting furnace 1 onto the float bath 2. Then, the molten glass spreads uniformly on the surface of the tin bath 2 a, forms a ribbon-shaped glass 9 having a constant width, and flows toward the outlet of the float bath 2 while being gradually cooled on the float bath 2. During this time (with a glass temperature of 600 ° C. (: 750 ° C.)), a film is formed by thermal decomposition CVD.

That is, a mixed gas of monosilane, ethylene, and oxygen diluted with nitrogen is ejected from a spray device 5 disposed on the float bath 2 as a Si raw material-containing gas for forming a silicon oxide film as the first layer. A gas mixture containing dimethyltin dichloride (steam), oxygen and water diluted with nitrogen is spouted from the spraying device 6 as a Sn material-containing gas for forming a tin oxide film as the second layer, and the spraying device 7 The same Si material-containing gas as described above, which forms a silicon oxide film as the third layer, is ejected from the spraying device 8, and the spray material 8 forms a Sn oxide film as the fourth layer. A mixture of dichloride (steam), oxygen, nitrogen and hydrogen fluoride (steam) Eject gas.

The spraying devices 5, 6, 7, 8 can be moved up and down freely so as to be able to freely adjust to the thickness of the glass or the thickness of the target coating.

In the vicinity of the outlet of the float bath 2, the glass is cooled to about 600 ° C., which is not deformed even when placed on a roll. Then, the strip glass exiting the float bath 2 is sent into the slow cooling unit 4 via the lift-out roll 3.

As the silicon raw material for forming the silicon oxide film, in addition to the above-mentioned monosilane, disilane, trisilane, monochlorosilane, 1,2-dimethylsilane, 1,1,2-trimethyldisilane, 1,1,2, A silane compound such as 2-tetramethyldisilane, tetramethylorthosilicate, tetraethylorthosilicate, or the like can be used. Oxidizing raw materials include oxygen, steam, dry air, carbon dioxide, carbon monoxide, and carbon dioxide. Nitrogen, ozone, etc. can be used.

When a silane compound is used as the silicon raw material, the reaction of the silane compound is suppressed until the silane compound reaches the surface of the glass substrate, and the refractive index of the silicon oxide film is controlled. For this purpose, it is also preferable to appropriately add an unsaturated hydrocarbon such as ethylene, acetylene or toluene.

In addition to the above-mentioned dimethyltin dichloride, from the viewpoint of increasing the conductivity, the tin raw material for forming the tin oxide film may be monobutyltin trichloride, tin tetrachloride, dibutyltin dichloride, or dioctyltin. A tin compound containing chlorine, such as dichloride, is preferred. Oxygen, water vapor, dry air and the like can be used as the oxidizing material.

When fluorine is added to the conductive film, examples of the fluorine raw material include hydrogen fluoride, trifluoroacetic acid, bromotrifluoromethane, and chlorodifluoromethane.

As a method of forming a metal oxide thin film on a glass substrate, a vacuum evaporation method, a sputtering method, a coating method, or the like can be applied. In consideration of the productivity and durability (peeling resistance) of the film, it is preferable to use a spray method such as a CVD method, a melt spray method, a dispersion liquid spray method, and a powder spray method.

In the embodiment, the raw material gas is sprayed on the glass surface on the float bath in the on-line CVD apparatus, but the CVD apparatus may be arranged on the downstream side of the float bath, that is, at a location where the cooling section is provided. .

FIG. 2 is an enlarged cross-sectional view of the low-emissivity glass obtained by the above-mentioned on-line CVD. In Example 1, a silicon oxide film as a first layer was formed on a glass substrate by 10 OA. A tin oxide film as a second layer is formed thereon with a thickness of 25 OA, and a silicon oxide film as a third layer is formed thereon with a thickness of 25 OA. On this, a tin oxide film as a fourth layer is formed with a thickness of 3500 A.

In Example 2, the thickness of the silicon oxide film as the first layer was set to 5 OA, and the second layer, the third layer, and the fourth layer were manufactured in the same manner as in Example 1. In Example 3, the thickness of the silicon oxide film as the first layer was set to 10 A, and the second layer, the third layer, and the fourth layer were manufactured in the same manner as in Example 1. On the other hand, a device without the silicon oxide film of the first layer was manufactured as a comparative example.

For each of the above Examples and Comparative Examples, the haze ratio was measured using an integrating sphere light transmittance measuring device (1101 ^ [-20?] Manufactured by Suga Test Instruments Co., Ltd.). In addition, turbidity was visually observed. The relationship between the haze ratio and the thickness of the first silicon oxide film is shown in the following (Table). Example 1 Example 2 Example 3 Comparative Example Thickness of First Layer Silicon Oxide Film (A) 100 00 501 0 0 Haze Ratio of Low-E Film (%) 0.4 0.4 1. 0 1.5 When the silicon oxide film of the first layer is 1 OA or more, the alkali barrier function is sufficiently exhibited, and the haze ratio is 1.0% or less. When the haze ratio becomes 1.0% or less, cloudiness (white turbidity) can be surely suppressed. For this reason, this low-emissivity glass can be used in applications where appearance is important, such as frozen showcases and show windows.

In addition, the first layer of the silicon oxide film has its alkali barrier function at 50 A at about 50 A, so even if it is formed too thick, it is only uneconomical. Therefore, the thickness of the first silicon oxide film is preferably from 10 to 100 A, and more preferably from 50 to 100 A.

The glass substrates of Examples 1 and 2 had a haze ratio of 0.4%, exhibited no turbid appearance, and exhibited excellent heat insulating properties. On the other hand, the glass substrate of the comparative example had a haze ratio (haze value) of 1.5% and was turbid. If the haze exceeds 1%, the glass will appear to be dirty because it has a slightly cloudy appearance compared to regular glass. Further, it is considered that the commercial value of the window glass is lost when the haze ratio rises to about 2%.

The haze ratio was measured using an integrating sphere light transmittance measuring device (HGM-2DP, manufactured by Suga Test Instruments Co., Ltd.). Turbidity was confirmed visually.

The use of the low-emissivity glass according to the present invention is not limited to windows for buildings and displays, but can also be applied to general industrial applications such as window glasses for automobiles, frozen showcases, and the like. It is also possible to achieve higher performance by interposing a transparent conductive film or a heat radiation film. Industrial applicability

As described above, according to the present invention, since the silicon oxide film is formed as the first layer on the surface of the glass substrate, it is possible to prevent Na (alkali) from diffusing from the glass, and to use online CVD. Also, no NaCl is generated in the conductive film. A low-emissivity glass having a low appearance rate and a good appearance can be obtained.

Since it is not necessary to control the temperature of the glass substrate when forming a film by online CVD, it is possible to reduce the cost of equipment by adding equipment such as a cooler, and to change the production speed of the glass. Does not have a high haze ratio and can use online CVD, which facilitates the design of the second and subsequent layers that are stacked for the purpose of reducing the emission color.

Furthermore, since the first layer that is in direct contact with the glass substrate is made of silicon oxide, there is almost no difference in the refractive index from the glass substrate, and the effect of reducing the reflection color by the second and third layers is utilized to achieve optical A very low emissivity glass can be obtained.

Claims

The scope of the claims

1. A silicon oxide film was formed as a first layer, a tin oxide film was formed as a second layer, a silicon oxide film was formed as a third layer, and a tin oxide film was formed as a fourth layer on the surface of an alkali-containing glass substrate. A low-emissivity glass characterized in that:

2. The low-emissivity glass according to claim 1, wherein the tin oxide film of the fourth layer contains F (fluorine).

3. In the low-emissivity glass according to claim 1 or 2, the thickness of the silicon oxide film as the first layer is 1 OA or more, and the thickness of the tin oxide film as the second layer is 2 OA. The thickness of the silicon oxide film as the third layer is from 200 to 500 A, and the thickness of the tin oxide film as the fourth layer is at least 250 OA. Low emissivity glass that is the feature.